1.Live cholera vaccine Inaba CVD 103-HgR was studied in mice for its possible pathogenicity in comparison with the parental virulent strain by using two routes of inoculation of animals (intraperitoneal and intranasal, i.e. "lung model"). The study revealed a low sensitivity of mice to cholera toxin and. therefore, demonstrated that the mouse system is not suitable for evaluation of safety of live cholera vaccines. 2.At the same time immunization of mice with the CVD 103-HgR vaccine provides a high protection against challenge with cholera toxin, suggesting, therefore, that the mouse test may be employed for evaluation of anticholeratoxic immunogenicity of live cholera vaccines with B subunit.